Process for the dry distillation of materials containing-cellulose.



supply UNITED STATES PATENT OFFICE.

HEINRICH VON HOCHSTETTER, OF CONSTANCE, GERMANY, ASSIGNOR TO THE FIRM OFHOLZVERKOHLUNGS-INDUSTRIE AKTIEN-GESELLSCHAFT, OF CONSTANCE, BADENIA,GERMANY, A CORPORATION OF GERMANY.

PROCESS FOR THE DRY DISTILLATION OF MATERIALS CONTAINING' CELLULOSE.

No Drawing.

To all whom it may concern.

Be it known that I, HEINRICH VON HOGH- s'rm'run, a subjectpf the Emperorof Austria, and resident of Constance, Badenia, (iermany, have inventedcertain new and useful Improvements in Processes for the DryDistillation of Materials Containing Cellulose, of which the followingis a specification.

Various processes and apparatus have been used in the wood charringindustry for the dry distillation of cellulose containing materials butthe mode of operation in all the processes is practically the same andis charm'rtcrized by three different stages (see M. Klar, Teclmologz'cof Wood Chewing, lierlin, Julius Springer, 1910, page 100) which are asfollows:

The initial stage which is the period of drying and heating the wood to280 degrees centigrade. The intermediate stage of the charringproper-and the final stage which consists in the concentration of thecarbon content in the charcoal, and therefore the heating of the latter,from 280 to about, 400 degrees centigrade.

During the initial and final periods a large quantity of heat has beenhitherto supplied while the intermediate period of the charring properof the wood required but little or no supply of heat (see Klar page 100,line 9 from the end of the page).

In following this mode of operation, in which the charring period pro erwas not at all or but little influenced the yield of acetate of lime wasalways the same within certain limits in spite of. the numerous andvaried forms of apparatus. It was even supposed that the slower thedistillation process was carried out, the greater would be the yield ofacetic acid (see Muspratt, Techn. Uhcmz'e, Vol. II, 1889, p. 1842, lines22 et seq.)

In contradistinction to this view the surprising observation has nowbeen made, that the yield of acetate of lime undergoes a con- 'siderableincrease, if the charrin proper (the period ofself-charrmg) be made asshort as possible, z. 0., that as soon as one notices any sign of anexothermic Specification of Letters Patent.

y the heat period I Patented Oct. 2, 191 '7.

Application filed April 2, 1913. Serial No. 758,435.

reaction taking place within the retort the supply of heat is soconsiderably and forcefully increased that from this time on thetemperature prevailing in the retort for the further run of thedistillation is about 400 centigrade or higher. In accordance with thisinvention this result is obtained by sup plyinr either directly orindirectly such COHSIC erable quantities of heat to the wood to hecharred during the distillation period, that the distillation of thegases of the gasifiable constituents is effected in a considerablyshorter period of time. The yield of wood spirit is in nowise affectedby'this mode of operation. Although the application of heat for thecondensation of the distillates is somewhat greater than that used inthe older mode of operation, this is compensated for by the greateryield of acetic acid. Moreover the new distillation process possessesthe further important advantage. that in consequence of the reduction oftime occupied by the distillation considerably more wood can be dealtwith in a given apparatus, than has been the case hitherto.

In the hereinbefore described process, care must of course be taken toavoid any injurious overheating of the material to .be charred.

I claim:

l. The process of distilling hardwood for the production of acetic acid,alcohol and charcoal which comprises continuously supplying heat duringthe period of exothermic reaction within the retort.

2. The process of distilling hardwood for the production of acetic acid,alcohol and charcoal which comprises raising the temperature Within theretort at the beginning of the period of exothermic reaction toapproximately 400 and maintaining that temperature throughout theprocess.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

HEINRICH VON HOCHBTETTER.

Witnesses:

Fnrrz Sonanrrnn,

Frances K. JEWE'I'I.

